Filter replacement lifetime prediction

ABSTRACT

A system for increasing filter economy includes a memory configured to receive measurements of contaminants in an internal and an external environment. A cost effectiveness module is configured to determine a cost of a corrosion rate increase if unfiltered external air intake is increased for cooling, to determine a cost of increased air pressure to filter external air, and to determine if the cost of filtering external air exceeds the cost of the corrosion rate increase. An air intake module is configured to increase an intake of unfiltered external air if it is determined that the cost of filtering external air exceeds the cost of the corrosion rate increase.

RELATED APPLICATION INFORMATION

This application is a Divisional application of co-pending U.S. patentapplication Ser. No. 13/847,255 filed on Mar. 19, 2013, incorporatedherein by reference in its entirety.

STATEMENT OF GOVERNMENT RIGHTS

This invention was made with Government support under Contract No.:DEEE0002897 awarded by Department of Energy. The Government has certainrights in this invention.

BACKGROUND

1. Technical Field

The present invention relates to the use of outdoor air for cooling datacenters and, more particularly, to maintaining contamination level inthe facility by using air contamination data and to predicting theeffective lifetime of air conditioner filters in data centers.

2. Description of the Related Art

With the increasing computational power of IT equipment, the energyconsumed for cooling can grow to be similar to the energy consumed forcomputation. One way to reduce cooling is the use of outdoor air forcooling when temperature, relative humidity, and air contamination arewithin acceptable ranges. One concern for using outside air for coolingis the introduction of gaseous and particulate contamination in the datacenters. In general air filters can be used for removing thecontamination for the air but they can impede air flow across thefilter, requiring larger blower to maintain air flow, and can increasethe overall maintenance cost of the data centers.

Air filters can effectively remove particular and gaseous contamination,but they are expensive to maintain. Contamination may be highlylocation-dependent, with different contaminants present in differentquantities depending on the geographic area. As a result, filterreplacement time can vary substantially according to data centersettings and the orientation of its air intake. A recommended filterreplacement time is usually provided by manufacturers based on anaverage value between best-and worst-case scenarios and may not actuallyreflect the realities of a given installation.

The American Society of Heating, Refrigerating and Air-ConditioningEngineers (ASHRAE) issues guidelines regarding gaseous and particularcontamination in data centers. In 2011, the ASHRAE indicated that datacenters should maintain an environment having a copper reactivity rateof less than 300 angstroms per month and a silver reactivity rate ofless than 200 angstroms per month to maintain reliable equipmentoperation. Corrosion can be caused by both gaseous and particularcontamination, and particulate contamination may have further negativemechanical and electrical effects.

Cooling systems that perform heat transfer with external air provideeconomical heat dissipation but involve a greater exposure to externalcontaminants. Leaks are inevitable and impose a slow air exchangebetween the clean air inside the data center and the contaminatedexternal air.

SUMMARY

A system for increasing filter economy includes a memory configured toreceive measurements of contaminants in an internal and an externalenvironment. A cost effectiveness module is configured to determine acost of a corrosion rate increase if unfiltered external air intake isincreased for cooling, to determine a cost of increased air pressure tofilter external air, and to determine if the cost of filtering externalair exceeds the cost of the corrosion rate increase. An air intakemodule is configured to increase an intake of unfiltered external air ifit is determined that the cost of filtering external air exceeds thecost of the corrosion rate increase.

A system for increasing filter economy includes at least one sensorconfigured to provide the measurements of gaseous and particulatecontaminants in an internal and an external environment to a memory. Alifetime module is configured to determine a rate of filter consumptionbased on a filter effectiveness history and to determine a remainingfilter lifetime based on the determined rate of filter consumption. Acost effectiveness module comprising a processor configured to determinea cost of a corrosion rate increase if unfiltered external air intake isincreased for cooling, to determine a cost of increased air pressure tofilter external air, and to determine if the cost of filtering externalair exceeds the cost of the corrosion rate increase. An air intakemodule is configured to increase an intake of unfiltered external air ifit is determined that the cost of filtering external air exceeds thecost of the corrosion rate increase.

These and other features and advantages will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The disclosure will provide details in the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a diagram of a cooling system for a data center that usesexternal air cooling in accordance with the present principles;

FIG. 2 is a graph of filter effectiveness over time;

FIG. 3 is a diagram of a sensor-equipped filter with monitoringapparatus in accordance with the present principles;

FIG. 4 is a diagram of a sensor-equipped filter in accordance with thepresent principles;

FIG. 5 is a block/flow diagram of determining a filter lifetime inaccordance with the present principles;

FIG. 6 is a diagram of a filter monitor in accordance with the presentprinciples; and

FIG. 7 is a block/flow diagram of a method for improving cooling economyin accordance with the present principles.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the present invention provide dynamic cooling in datacenters situated in locations where the outside air has high gaseous andparticulate contamination during some periods of times of the year andwhere outside air is used for cooling. Embodiments of the presentinvention provide effectiveness monitoring for air filters that tracksmanufacturer specifications, real-time sensor data, and predictiveestimates of filter lifetime. Based on real-time measurements andpredictions, the useful lifetime of a filter can be effectively doubled,thus reducing the cost of maintenance. Cost-effective corrosion andparticulate sensors may be employed for both particulate and gaseouscontaminants to build an accurate determination of current filtereffectiveness. Such effectiveness may be tracked over time to build anestimate of the filter's useful lifetime. This allows site-specificmonitoring and management of filters.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1, an exemplary cooling systemis shown. A data center 102 uses an internal heat exchange 104 totransfer heat from one or more data center systems to air. The internalheat exchange 104 may include one or more of, e.g., radiators,liquid-cooling systems, fans, etc. The internal heat exchange maytransfer heat to the ambient air in the data center 102 or may use aclosed system to isolate transferred heat.

Data center 102 is isolated from the external environment by a barrier108. The barrier 108 should be understood as being an imperfect barrierthat allows a slow, but non-negligible, amount of air transfer betweenthe data center 102 and the external environment. This leakage providesa route for air-based contaminants to enter the otherwise closedenvironment of the data center 102. The leakage may come fromintentional openings in the barrier 108 (e.g., using outside air forcooling) or may be unintentional (e.g., leaks in the wall or imperfectisolation of the data center).

The internal heat exchange 104 provides heated air to an external heatexchange 106. External heat exchange 106 allow outside air to beintroduced directly in the data center to cool the IT equipment. The airmay pass through one or more air filters 110 that are designed to removegaseous and/or particular contaminants. Such filters 110 may be based onany appropriate filtering mechanism, including for example chemicalfilters, mechanical filters, catalytic filters, etc. For the purpose ofillustration, the filters 110 are shown as being directly in the path ofthe internal/external heat exchange, but such filters 110 may also beplaced to process standing air in the data center 102.

The data center 102 includes a number of systems, any of which may besusceptible to contaminants. Corrosion increasingly takes place due tothe increase of the air contamination across the globe, utilization ofoutside air for cooling, and use of non-lead solders in circuit boards.For example, copper creep corrosion is a corrosion of copper plating tocopper sulfide on printed circuit boards, causing copper sulfite tocreep over the surface of the circuit boards, potentially creatingelectric shorts between adjacent circuit-board features. As anotherexample, the corrosion of silver terminations to silver sulfide insurface-mounted components leads to the loss of silver metallizationand, ultimately, the breaking of an electrical connection in componentssuch as resistors.

Corrosion may be caused by such gaseous contaminants as nitric oxide,nitrogen dioxide, and sulfur dioxide. Most of the above gases arecommonly encountered in the atmosphere due to industrial activities, caremission, agricultural activities, etc. Corrosion rate is furthermoredriven by temperature and humidity, where higher temperature and higherrelative humidity increases the corrosion rate. Particular contaminants,such as ionic dust, may cause further corrosion, particularly when therelative humidity is high enough for the dust to become wet and,therefore, electrically conductive.

Referring now to FIG. 2, a graph illustrating filter aging is shown.This graph represents a copper corrosion rate on the vertical axis inangstroms per month and a filter lifetime on the horizontal axismeasured in months. The filter 110 in this example has a recommendedlifetime of six months. When the filter 110 is brand new it will mosteffectively capture the contaminants in the air and, such that thecorrosion rate will be very low. As the filter 110 ages, the filter 110will retain less of the corrosive molecules in the air and the corrosionrate will increase. An increased corrosion rate may also be the resultof an increase in the levels of outside pollution. However, in thisparticular environment, the filter 110 is still maintaining a corrosionrate below the recommended level of 300 angstroms per month after sixmonths. Indeed, the filter 10 appears to function within the guidelinesafter a full year of operation, indicating that it has a useful lifetimeeffectively double the recommended lifetime. If this information isavailable to data center managers, it not only provides them with theability to determine when filters 110 actually need to be replaced, butallows them to predict a future time when such replacement will be mosteconomical.

Referring now to FIG. 3, a filter lifetime prediction system 300 isshown. A filter 302 is placed in an air duct 310. An intake sensor 304is placed at the intake side of the filter 302 and an outlet sensor 306is placed on the outlet side. The sensors 304 and 306 monitor thepressure drop across the filter 302, making sure that enough air ispassed through the filter to ensure cooling of the data center. If thepressure drop increases, it is an early indicator that the filter isclogged and that the effectiveness of the air filtration provided byfilter 302 may decrease. This information provides warning as to whenthe filter 302 should be replaced.

It should be recognized that different type of sensors 304/306 may beemployed. These sensors may include, but are not limited to, corrosionsensors for gaseous contamination monitoring and dust/particle sensorsfor particulate contamination. A differential pressure sensor maymeasure the pressure drop across the filter 302 and indicate whether thefilter 302 is clogged or for some other reason not passing a usefulamount of air. The sensors 304/306 will have effective lifetimes oftheir own, as corrosion sensors may be consumed through use. The sensors304/306 may be selected to be directly correlated with the expectedeffective lifetime of the filter. The sensors 304/306 may be assembledin a relatively compact form. For example, the whole sensor assembly maybe of the order of a half-inch to a side and may be fastened directly tothe air filter 302. As such, the filter 302 and the sensors 304/306 maybe provided as a single package and replaced as a single unit.

Sensors 304/306 communicate with a filter monitor 308 that tracks andstores sensor data. The filter monitor 308 analyzes that data andprovides outputs regarding the current status and expected lifetime ofthe filter 302. The sensors 304/306 may communicate with the filtermonitor 308 via wired or wireless connections. It should be recognizedthat wireless connections are often preferable, as wiring may bedifficult to install in locations that filters are often used (such asduct 310), but wireless communications may similarly be difficult insuch contexts. Wireless communication protocols should be conducive tolow-power communications, as a true wireless solution will needself-contained power in the form of, e.g., an on-sensor battery. Thesensors may communicate using any appropriate protocol, includingwithout limitation Bluetooth, Wi Fi®, ZigBee®, etc.

Referring now to FIG. 4, an exemplary air filter 302 is shown. Thefilter 302 is illustrated face-on, with a filtering material 404 shown.The intake sensor 304 is mounted directly on the filtering material 404in this example, though it should be recognized that the sensor may alsobe mounted on the frame of the filter 302. A control module 402 ismounted on the frame of the filter 302 and communicates with the sensor304. The control module 402 may provide electrical power to the sensor304. Furthermore, if the filter 302 is slotted into position wheninstalled, the control module 402 may be mounted in such a manner as toremain exposed. This allows the control module 402 to provide effectivewireless data communication from a duct that would otherwise shield suchsignals.

For any sensor 306 that measures the effectiveness of a filter 302, thesignal will increase as the filter stays in the field. A threshold valuecan be present, as shown above in FIG. 2. The signal may be compared toa threshold value, either in filter monitor 308 or in control module402. If the sensor signal is below the threshold value, then the filterstatus is determined to be functional. If the signal exceeds thethreshold, then the filter is determined to be in need of replacement.Exceeding the threshold may also indicate that outside air may not beused for cooling. The filter monitor 308 issues a warning that thefilter 302 is not performing within an acceptable range may issue aninstruction to shut off cooling using outside air.

It should be recognized that the control module 402 may be the samecomponent as the filter monitor 308, such that the control module 402represents a self-contained unit. Alternatively, several control modules402 may communicate with the filter monitor 308 in a distributedfashion.

Referring now to FIG. 5, a method for estimating a future filterlifetime is shown. Block 502 collects information from sensors 304/306.This information reflects the nature of the particular sensor and mayrepresent, for example, air pressure differential, the presence ofspecific contaminants, corrosion rates, particulate density, etc. Sensorinformation 502 may be collected periodically, for example on a daily orseasonal basis. Block 504 updates historical information for one or morefilters 302 associated with the sensors 304/306. This historicalinformation may simply be a list of periodically measured sensor valuesor it can show gaseous pollutant variation over a certain period oftime. The prediction of filter lifetime is based on real time corrosionrate calculations from the corrosion sensor using Kalman filters topredict short term variation of the corrosion rate. The extrapolation isused to estimate when the filter performance will fall below acceptablelevels.

Block 506 checks whether the instantaneous values of the sensors 304/306exceed (or fall below) a threshold. The internal corrosion rate may bedetermined based on the outdoor corrosion rate. One formula for findingthe outdoor corrosion rate is as follows:

CR_(out)≈(H₂S)^(a)(SO₂)^(b)(NO₂)^(c)e^(d·RH)e^(E) ^(a) ^(/k) ^(B) ^(T),

where H₂S, SO₂, and NO₂ is are the gaseous contaminants hydrogensulfide, sulfur dioxide, and nitrous oxide in parts per billion, RH isthe relative humidity, E_(a) is the activation energy for a given metal,k_(B) is the Boltzmann constant, and the scaling variables a, b, c, andd are determined by fitting historical corrosion data versus variationof the gaseous pollutant concentration in a controlled or normalenvironment. The base corrosion rate can be determined when the gaseouscontaminant concentration is at acceptable levels for a data center.

The internal corrosion rate may be determined as follows:

${{CR}_{i\; n} = \frac{{CR}_{out}}{1 + {T^{f}{{RH}^{g}\left( {H_{2}S} \right)}^{h}\left( {SO}_{2} \right)^{i}\left( {NO}_{2} \right)^{j}}}},$

where the scaling variables f, g, h, i, and j are determined bymeasuring the corrosion rate indoors and correlating it with the outdoorcorrosion rate and gaseous concentration. These indoor scaling variablesmay be different from those outside, as chemical contaminants may alsoarise from internal sources, such as cleaning chemicals.

If the corrosion rate exceeds (or falls below) the threshold, block 508issues a warning. If the instantaneous value of the sensors 304/306 goespast this threshold, it may indicate pollution levels are high. In thiscase, the outside air used for cooling should be shut off. If thecorrosion rate remains high it may be an indication that the filter 302has become damaged. In one example, physical damage to the filter 302might result in an air pressure differential that is too low, while aphysical obstruction of the filter 302 might result in a differentialthat is too high. Either condition should be addressed quickly, and thewarning issued by block 508 may provide an operator with informationregarding the fault and how to fix it. In a similar way, particularlyharsh environmental conditions (such as a forest fire or pollen season)may be accounted for, allowing for automated shutoff of outside airintake to limit further contamination.

Block 510 uses the filter history to determine a rate of filterconsumption. Block 510 may employ a statistical analysis to compare thefilter history to known filter characteristics or may use a time seriesanalysis such as a Kalman filter model. Using a Kalman filter model,future values may be predicted and a remaining lifetime may be computed.The Kalman filter allows the elimination of noise associated with, e.g.,corrosion rate measurements that may arise due to changes in temperatureand relative humidity that accelerate or reduce corrosion rate on ashort-term basis. In addition, a Kalman filter model may estimate theeffectiveness of the filter 302 under reduced air flow conditions, suchas when the amount of air flow is reduced due to clogging by particulatematter.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing. Computer program code for carrying out operations foraspects of the present invention may be written in any combination ofone or more programming languages, including an object orientedprogramming language such as Java, Smalltalk, C++ or the like andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The program codemay execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (LAN) or a wide area network (WAN), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer, other programmable data processing apparatus, orother devices to cause a series of operational steps to be performed onthe computer, other programmable apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblocks may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

Referring now to FIG. 6, a block diagram of a filter monitor 308 isshown. The filter monitor includes a hardware processor 602 and memory604. A network adapter 605 communicates with one or more sensors 304/306and receives sensor measurement information. A filter history 606 ismaintained in memory 604 based on the information received from sensors304/306, maintaining a table of sensor values for one or more associatedfilters 302. Lifetime module 608 uses processor 602 to calculate anestimated lifetime for the filter 302 based on analysis of the filterhistory 606. A warning module 610 may be configured to respond toinstantaneous sensor information that exceeds or falls below acceptablethresholds. If this occurs, warning module 610 notifies a user or systemoperator of the problem, allowing quick resolution. A cost effectivenessmodule 612 allows the filter monitor 308 to alter air intake patterns,for example by bypassing the filter 302 if external conditions permit.

Referring now to FIG. 7, a block/flow diagram of a method for filterbypass is shown. In some cases, the contaminants in the externalenvironment may be low enough that such air may be used directly,without filtration. Thus, if the costs incurred by using unfiltered airare lower than the cost of the energy expended forcing air through afilter, it becomes more economical to simply use the unfiltered air.

Block 702 measures the internal and external environments using sensors304/306. These measurements may include, for example, corrosion rates,temperature, and relative humidity. Block 704 compares, e.g., theinternal corrosion rate to a guideline corrosion rate. If the internalcorrosion rate is higher than the guideline level, block 705 decreasesthe intake of unfiltered air from the external environment. Thisrepresents a scenario where, for example, the level of contaminants inthe outside air increases, such that more filtration is needed. This isa separate consideration from that described above with respect to FIG.5—a transient spike in external corrosion rate may temporarily raise theinternal corrosion rate beyond guideline levels without necessitatingfilter replacement.

If the internal corrosion rate at block 704 is below the guidelinelimit, then block 706 determines whether additional cooling is needed.If the internal temperature is not above guideline levels, the no changeis needed and processing returns to block 702 to measure theenvironments again after some delay. It should be recognized that thisconsideration need not be limited to temperature. For example, the sameconsideration may be applied for internal relative humidity.

If the temperature has risen above guideline levels, then block 708performs a cost/benefit analysis regarding the use of unfiltered air.Using unfiltered air takes less energy, as the air does not need to beforced through a filter. As a result, the economic efficiency of usingunfiltered air may be compared to a cost of increased internalcorrosion. If block 710 determines that the cost of filtering the air isgreater than the cost of the marginal increase in internal corrosionrate, block 712 increases the intake of unfiltered air. Otherwise, block714 decreases the intake of unfiltered air.

Changing the unfiltered air intake in block 705, 712, or 714 will havean impact on the predicted lifetime of the filter 302. Block 716 updatesthe filter lifetime prediction described above with respect to block512. As the intake of unfiltered air increases, the estimated lifetimeof the filter 302 can be expected to increase, as less air will bepushed through. On the other hand, as the intake of unfiltered airdecreases, the difference will be made up in an increase of air throughthe filter 302, thereby decreasing the expected lifetime.

Having described preferred embodiments of a system and method for filterreplacement lifetime prediction (which are intended to be illustrativeand not limiting), it is noted that modifications and variations can bemade by persons skilled in the art in light of the above teachings. Itis therefore to be understood that changes may be made in the particularembodiments disclosed which are within the scope of the invention asoutlined by the appended claims. Having thus described aspects of theinvention, with the details and particularity required by the patentlaws, what is claimed and desired protected by Letters Patent is setforth in the appended claims.

What is claimed is:
 1. A system for increasing filter economy,comprising: a memory configured to receive measurements of contaminantsin an internal and an external environment; a cost effectiveness modulecomprising a processor configured to determine a cost of a corrosionrate increase if unfiltered external air intake is increased forcooling, to determine a cost of increased air pressure to filterexternal air, and to determine if the cost of filtering external airexceeds the cost of the corrosion rate increase; and an air intakemodule configured to increase an intake of unfiltered external air if itis determined that the cost of filtering external air exceeds the costof the corrosion rate increase.
 2. The system of claim 1, furthercomprising a lifetime module configured to determine a rate of filterconsumption based on a filter effectiveness history.
 3. The system ofclaim 2, wherein the rate of filter consumption characterizes a changeover time in a degree of unfiltered contamination.
 4. The system ofclaim 3, wherein the lifetime module is further configured to determinea remaining filter lifetime as a time remaining until the degree ofunfiltered contamination is predicted to exceed a threshold.
 5. Thesystem of claim 4, wherein the lifetime module is further configured toupdate a predicted filter lifetime based on an intake of unfilteredexternal air.
 6. The system of claim 1, further comprising a warningmodule configured to provide a warning if the sensor informationassociated with the filter exceeds an instantaneous failure threshold.7. The system of claim 6, wherein the instantaneous failure thresholdrepresents a physical failure of the filter.
 8. The system of claim 6,wherein the instantaneous failure threshold represents a degree ofunfiltered contamination substantially in excess of a guideline level.9. The system of claim 1, wherein the cost effectiveness module isfurther configured to determine whether external conditions are withinguideline levels for temperature, relative humidity, and corrosion rate.10. The system of claim 9, wherein the air intake module is furtherconfigured to decrease the intake of unfiltered external air if externalconditions fall outside of guideline levels.
 11. The system of claim 1,further comprising at least one sensor configured to provide themeasurements of contaminants to the memory.
 12. The system of claim 11,wherein the contaminant sensor information includes sensor informationfor gaseous and particulate contaminants.
 13. A system for increasingfilter economy, comprising: at least one sensor configured to providethe measurements of gaseous and particulate contaminants in an internaland an external environment to a memory; a lifetime module configured todetermine a rate of filter consumption based on a filter effectivenesshistory and to determine a remaining filter lifetime based on thedetermined rate of filter consumption; a cost effectiveness modulecomprising a processor configured to determine a cost of a corrosionrate increase if unfiltered external air intake is increased forcooling, to determine a cost of increased air pressure to filterexternal air, and to determine if the cost of filtering external airexceeds the cost of the corrosion rate increase; and an air intakemodule configured to increase an intake of unfiltered external air if itis determined that the cost of filtering external air exceeds the costof the corrosion rate increase.
 14. The system of claim 13, wherein therate of filter consumption characterizes a change over time in a degreeof unfiltered contamination.
 15. The system of claim 14, wherein thelifetime module is further configured to determine a remaining filterlifetime as a time remaining until the degree of unfilteredcontamination is predicted to exceed a threshold and to update apredicted filter lifetime based on an intake of unfiltered external air.16. The system of claim 1, further comprising a warning moduleconfigured to provide a warning if the sensor information associatedwith the filter exceeds an instantaneous failure threshold.
 17. Thesystem of claim 6, wherein the instantaneous failure thresholdrepresents a physical failure of the filter.
 18. The system of claim 6,wherein the instantaneous failure threshold represents a degree ofunfiltered contamination substantially in excess of a guideline level.19. The system of claim 1, wherein the cost effectiveness module isfurther configured to determine whether external conditions are withinguideline levels for temperature, relative humidity, and corrosion rate.20. The system of claim 19, wherein the air intake module is furtherconfigured to decrease the intake of unfiltered external air if externalconditions fall outside of guideline levels.